Efficient and stable inverted perovskite solar cells with very high fill factors via incorporation of star-shaped polymer

Qi Cao; Yongjiang Li; Hong Zhang; Jiabao Yang; Jian Han; Ting Xu; Shuangjie Wang; Zishuai Wang; Bingyu Gao; Junsong Zhao; Xiaoqiang Li; Xiaoyan Ma; Shaik Mohammed Zakeeruddin; Wei E I Sha; Xuanhua Li; Michael Grätzel

doi:10.1126/sciadv.abg0633

Efficient and stable inverted perovskite solar cells with very high fill factors via incorporation of star-shaped polymer

Sci Adv. 2021 Jul 7;7(28):eabg0633. doi: 10.1126/sciadv.abg0633. Print 2021 Jul.

Authors

Qi Cao¹, Yongjiang Li², Hong Zhang³, Jiabao Yang¹, Jian Han¹, Ting Xu⁴, Shuangjie Wang¹, Zishuai Wang⁵, Bingyu Gao¹, Junsong Zhao¹, Xiaoqiang Li¹, Xiaoyan Ma², Shaik Mohammed Zakeeruddin³, Wei E I Sha⁴, Xuanhua Li⁶, Michael Grätzel⁷

Affiliations

¹ State Key Laboratory of Solidification Processing, Center for Nano Energy Materials, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi'an 710072, China.
² The Key Laboratory of Space Applied Physics and Chemistry, School of Chemistry and Chemical Engineering, Northwestern Polytechnical University, Xi'an 710072, China.
³ Laboratory of Photonics and Interfaces, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland.
⁴ Key Laboratory of Micro-Nano Electronic Devices and Smart Systems of Zhejiang Province, Zhejiang University, Zhejiang 310027, China.
⁵ Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong.
⁶ State Key Laboratory of Solidification Processing, Center for Nano Energy Materials, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi'an 710072, China. michael.graetzel@epfl.ch lixh32@nwpu.edu.cn.
⁷ Laboratory of Photonics and Interfaces, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland. michael.graetzel@epfl.ch lixh32@nwpu.edu.cn.

Abstract

Stabilizing high-efficiency perovskite solar cells (PSCs) at operating conditions remains an unresolved issue hampering its large-scale commercial deployment. Here, we report a star-shaped polymer to improve charge transport and inhibit ion migration at the perovskite interface. The incorporation of multiple chemical anchor sites in the star-shaped polymer branches strongly controls the crystallization of perovskite film with lower trap density and higher carrier mobility and thus inhibits the nonradiative recombination and reduces the charge-transport loss. Consequently, the modified inverted PSCs show an optimal power conversion efficiency of 22.1% and a very high fill factor (FF) of 0.862, corresponding to 95.4% of the Shockley-Queisser limited FF (0.904) of PSCs with a 1.59-eV bandgap. The modified devices exhibit excellent long-term operational and thermal stability at the maximum power point for 1000 hours at 45°C under continuous one-sun illumination without any significant loss of efficiency.

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